1 #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_GCC_PPC_HPP_INCLUDED
2 #define BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_GCC_PPC_HPP_INCLUDED
3
4 // MS compatible compilers support #pragma once
5
6 #if defined(_MSC_VER) && (_MSC_VER >= 1020)
7 # pragma once
8 #endif
9
10 //
11 // detail/sp_counted_base_gcc_ppc.hpp - g++ on PowerPC
12 //
13 // Copyright (c) 2001, 2002, 2003 Peter Dimov and Multi Media Ltd.
14 // Copyright 2004-2005 Peter Dimov
15 //
16 // Distributed under the Boost Software License, Version 1.0. (See
17 // accompanying file LICENSE_1_0.txt or copy at
18 // http://www.boost.org/LICENSE_1_0.txt)
19 //
20 //
21 // Lock-free algorithm by Alexander Terekhov
22 //
23 // Thanks to Ben Hitchings for the #weak + (#shared != 0)
24 // formulation
25 //
26
27 #include <boost/detail/sp_typeinfo.hpp>
28
29 namespace boost
30 {
31
32 namespace detail
33 {
34
atomic_increment(int * pw)35 inline void atomic_increment( int * pw )
36 {
37 // ++*pw;
38
39 int tmp;
40
41 __asm__
42 (
43 "0:\n\t"
44 "lwarx %1, 0, %2\n\t"
45 "addi %1, %1, 1\n\t"
46 "stwcx. %1, 0, %2\n\t"
47 "bne- 0b":
48
49 "=m"( *pw ), "=&b"( tmp ):
50 "r"( pw ), "m"( *pw ):
51 "cc"
52 );
53 }
54
atomic_decrement(int * pw)55 inline int atomic_decrement( int * pw )
56 {
57 // return --*pw;
58
59 int rv;
60
61 __asm__ __volatile__
62 (
63 "sync\n\t"
64 "0:\n\t"
65 "lwarx %1, 0, %2\n\t"
66 "addi %1, %1, -1\n\t"
67 "stwcx. %1, 0, %2\n\t"
68 "bne- 0b\n\t"
69 "isync":
70
71 "=m"( *pw ), "=&b"( rv ):
72 "r"( pw ), "m"( *pw ):
73 "memory", "cc"
74 );
75
76 return rv;
77 }
78
atomic_conditional_increment(int * pw)79 inline int atomic_conditional_increment( int * pw )
80 {
81 // if( *pw != 0 ) ++*pw;
82 // return *pw;
83
84 int rv;
85
86 __asm__
87 (
88 "0:\n\t"
89 "lwarx %1, 0, %2\n\t"
90 "cmpwi %1, 0\n\t"
91 "beq 1f\n\t"
92 "addi %1, %1, 1\n\t"
93 "1:\n\t"
94 "stwcx. %1, 0, %2\n\t"
95 "bne- 0b":
96
97 "=m"( *pw ), "=&b"( rv ):
98 "r"( pw ), "m"( *pw ):
99 "cc"
100 );
101
102 return rv;
103 }
104
105 class sp_counted_base
106 {
107 private:
108
109 sp_counted_base( sp_counted_base const & );
110 sp_counted_base & operator= ( sp_counted_base const & );
111
112 int use_count_; // #shared
113 int weak_count_; // #weak + (#shared != 0)
114
115 public:
116
sp_counted_base()117 sp_counted_base(): use_count_( 1 ), weak_count_( 1 )
118 {
119 }
120
~sp_counted_base()121 virtual ~sp_counted_base() // nothrow
122 {
123 }
124
125 // dispose() is called when use_count_ drops to zero, to release
126 // the resources managed by *this.
127
128 virtual void dispose() = 0; // nothrow
129
130 // destroy() is called when weak_count_ drops to zero.
131
destroy()132 virtual void destroy() // nothrow
133 {
134 delete this;
135 }
136
137 virtual void * get_deleter( sp_typeinfo const & ti ) = 0;
138 virtual void * get_local_deleter( sp_typeinfo const & ti ) = 0;
139 virtual void * get_untyped_deleter() = 0;
140
add_ref_copy()141 void add_ref_copy()
142 {
143 atomic_increment( &use_count_ );
144 }
145
add_ref_lock()146 bool add_ref_lock() // true on success
147 {
148 return atomic_conditional_increment( &use_count_ ) != 0;
149 }
150
release()151 void release() // nothrow
152 {
153 if( atomic_decrement( &use_count_ ) == 0 )
154 {
155 dispose();
156 weak_release();
157 }
158 }
159
weak_add_ref()160 void weak_add_ref() // nothrow
161 {
162 atomic_increment( &weak_count_ );
163 }
164
weak_release()165 void weak_release() // nothrow
166 {
167 if( atomic_decrement( &weak_count_ ) == 0 )
168 {
169 destroy();
170 }
171 }
172
use_count() const173 long use_count() const // nothrow
174 {
175 return static_cast<int const volatile &>( use_count_ );
176 }
177 };
178
179 } // namespace detail
180
181 } // namespace boost
182
183 #endif // #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_GCC_PPC_HPP_INCLUDED
184